My Orange Laser Corys (some not all) have developed some sort of abnormality. It appears that their scales have become a bit agitated. Not exactly sure what it is. Anyone have experience with this? For the most part it runs in a line on their side and along their spine. No other fish, including other types of corys, have it.
water temp is 73 F
Nitrate and nitrite close to zero
PH is 7